Category: New York

How to Design Rail Service to Connect to Buses Better

Usually, integrated transit planning means designing bus networks to feed rail trunks better. Buses are mobile: their routes can move based on long-term changes in the city’s physical and economic layout. Railroads in contrast have high installation costs. Between the relative ease of moving buses and the fact that there’s a hierarchy in which trains are more central than buses, buses normally should be feeding the trains. However, there are some cases in which the opposite happens: that is, cases in which it’s valuable to design rail infrastructure based on expected bus corridors. Moreover, in developed and middle-income countries these situations are getting more rather than less frequent, due to the increasing use of deep tunneling and large station complexes.

In nearly every circumstance, the hierarchy of bus and rail remains as it is; the exceptions (like Ottawa, at least until the light rail subway opens) are so rare as to be notable. What I posit is that in some situations, rail infrastructure should be designed better to allow buses to feed the trains more efficiently. This mostly affects station infrastructure, but there are also reasons to choose routes based on bus feeding.

Major bus corridors

Surface transit likes following major streets. Years ago, I blogged about this here and here. Major streets have two relevant features: they are wide, permitting buses (or streetcars) to run in generous dedicated lanes without having to deal with too much traffic; and they have continuous linear development, suitable for frequent bus stops (about every half kilometer).

These two features are likely to remain important for surface transit for the foreseeable future. The guidelines for good surface transit service depend on empirical parameters like the transfer penalty (in particular, grids are not the universal optimum for bus networks), but major corridors are relatively insensitive to them. The walk penalty can change the optimal bus stop spacing, but not in a way that changes the basic picture of corridor-based planning. Which streets have the most development is subject to change as city economic and social geography evolves, but which streets are the widest doesn’t. What’s more, a train station at a street intersection is likely to cement the cross-street’s value, making adverse future change less likely.

Note that we don’t have to be certain which major streets will host the most important buses in the future. We just need to know that major buses will follow major streets.

The conclusion is that good locations for rail infrastructure are major intersecting streets. On a commuter line, this means stations should ideally be placed at intersections with roads that can carry connecting buses. On a subway line, this means the same at a more local scale.

Stations and accessibility

When possible, train stations should locate at intersections with through-streets, to permit efficient transfers. This also carries over to station exits, an important consideration given the complexity of many recently-built stations in major rich and middle-income cities.

It goes without saying that a Manhattan subway line should have stations with exits at 72nd, 79th, 86th, 96th, etc. streets. Here, Second Avenue Subway does better than the Lexington Avenue Line, whose stations are chosen based on a 9-block stop spacing and miss the intersecting buses.

However, it’s equally important to make sure that the accessible exits are located at major streets as well. One bad example in New York is the Prospect Park B/Q station: it has two exits, one inaccessible on Flatbush Avenue and one accessible on Empire Boulevard. In theory both are major corridors, but Flatbush is far and away the more important ones, one of the busiest surface transit corridors in the city, while Empire competes for east-west buses with Kings County Hospital, the borough’s biggest job center outside Downtown Brooklyn. Eric Goldwyn’s and my Brooklyn bus redesign breaks the B41 bus on Flatbush and loops it and the Washington Avenue routes around the station complex to reach the accessible exit.

The Prospect Park case is one example of an almost-right decision. The full-time, accessible exit is close to Flatbush, but not quite there. Another example is Fields Corner: the eastern end of the platform is 80 meters from Dorchester Avenue, a major throughfare, and 180 meters from Adams Avenue, another major street, which unlike Dot Ave diverges from the direction the Red Line takes on its way south and is a useful feeder bus route.

Commuter rail and feeder buses

The station placement problem appears especially acute on mainline rail. This is not just an American problem: suburban RER stations are built without regard for major crossing roads (see, for example, the RER B airport branch and the RER A Marne-la-Vallee branch, both built in the 1970s). Railroads historically didn’t think much in terms of systemwide integration, but even when they were turned into modern rapid transit, questionable stop locations persisted; the Ashmont branch of the Red Line in Boston was taken over from mainline rail in the 1920s, but Fields Corner was not realigned to have exits at Dot and Adams.

Today, the importance of feeder buses is better-understood, at least by competent metropolitan transportation planners. This means that some stations need to be realigned, and in some places infill stops at major roads are desirable.

This is good for integration not just with buses but also with cars, the preferred station access mode for American commuter rail. The LIRR’s stations are poorly located within the Long Island road network; Patrick O’Hara argues that Hicksville is the second busiest suburban station (after Ronkonkoma) not because it preferentially gets express service on the Main Line, but because it has by far the best north-south access by road, as it has one arterial heading north and two heading south, while most stations miss the north-south arterials entirely.

Instead of through-access by bus (or by car), some stations have bus bays for terminating buses. This is acceptable, provided the headways are such that the entire local bus network can be configured to pulse at the train station. If trains arrive every half hour (or even every 20 minutes), then timed transfers are extremely valuable. In that case, allowing buses to stop at a bay with fast access to the platforms greatly extends the train station’s effective radius. However, this is of far less value on a dense network with multiple parallel lines, or on a railroad so busy that trains arrive every 10 minutes or less, such as the RER A branches or the trunks of the other RER lines.

Within New York, we see this mistake of ignoring local transit in commuter rail planning with Penn Station Access. The project is supposed to add four stations in the Bronx, but there will not be a station at Pelham Parkway, the eastern extension of Fordham Road carrying the city’s busiest bus, the Bx12. This is bad planning: the MTA should be encouraging people to connect between the bus and the future commuter train and site stations accordingly.

Street networks and route choice

On a grid, this principle is on the surface easy: rapid transit routes should follow the most important routes, with stops at cross streets. This is well understood in New York (where proposals for subway extensions generally follow busy bus routes, like Second Avenue, Nostrand, and Utica) and in Vancouver (where the next SkyTrain extension will follow Broadway).

However, there remains one subtlety: sometimes, the grid makes travel in one direction easier than in another. In Manhattan, north-south travel is easier than east-west travel, so in isolation, east-west subways connecting to north-south buses would work better. (In reality, Manhattan’s north-south orientation means north-south subways are indispensable, and once the subways exist, crossing subways should aim to connect to them first and to surface transit second.) In West Los Angeles, there is a multitude of east-west arterials and a paucity of north-south ones, which means that a north-south subway is of great value, connecting not just to the Expo Line and upcoming Wilshire subway but also other east-west arterials carrying major bus routes like Olympic.

Moreover, some cities don’t have intact grids at all. They have haphazard street networks, with some routes suitable for arterial buses and some not. This is less of an issue in mature cities, which may have such street networks but also have older subway lines for newer route to connect to, and more in newer cities, typically in the third world.

The tension is that very wide arterials are easier to build on, using elevated construction or cut-and-cover. If such a technique is feasible, then constructibility should trump connections to buses (especially since such cities are fast-changing, so there is less certainty over what the major future bus routes are). However, if deep boring is required, for examples because the arterials aren’t that wide, or the subway must cross underwater, or merchant opposition to cut-and-cover is too entrenched, then it’s useful to select routes that hit the arterials orthogonally, for the best surface transit connections.

Conclusion

In a working transit city, rail should be the primary mode of travel and buses should be designed to optimally feed the trains. However, this does not mean rail should be planned without regard to the buses. Train stations should be sited based not just on walk sheds and major destinations but also planned bus connections; on an urban rapid transit system, including S-Bahn trunks, this means crossing arterial streets, where buses typically run. Moreover, these stations’ exits should facilitate easy transfers between buses and trains, including for people with disabilities, who face more constrained mobility choices if they require elevator access. In some edge cases, it may even be prudent to select entire route construction priorities based on bus connections.

While choosing rail routes based on bus connections seems to only be a real issue in rare circumstances (such as the West LA street network), bus-dependent station siting is common. Commuter train services in general are bad at placing stations for optimal suburban bus connections, and may require extensive realignment and infill. On urban subways, station placement is important for both accessibility retrofits and new projects. Outside city centers, where dense subway networks can entirely replace surface transit, it’s critical to select station sites based on maximum connectivity to orthogonal surface lines.

Port Authority’s LaGuardia Rail Link Study

Two days ago, Port Authority put out a study about a rail link to LaGuardia, which became Governor Cuomo’s top transit priority a few years ago. The PDF file is bundled with the RFP, but starting on PDF-p. 25 it’s an alternatives analysis and not an RFP. While transit activists including myself have attacked Cuomo’s proposed rail link for its poor alignment choice, the Port Authority study considers many alternatives, including some interesting ones. It also describes the current situation in more detail than I’ve seen elsewhere. I’d like to talk about the alternatives for a rail link, but also summarize some of the important facts buried in the study. Unfortunately, the study also eliminates all the useful options and prefers to advance only Cuomo’s uselessly circuitous alignment.

The current situation

LaGuardia had about 25 million O&D passengers in 2017. They disproportionately go to or from Midtown, but it’s not as overwhelming as I thought based on this density map. Here is a precise breakdown, lumping together both locals (33%) and visitors (67%):

In Manhattan and western Queens “Walking access” means half a mile from a commuter rail stop or from the 7 train; there is no attempt to track walk access to the N or W trains. In Eastern Queens it means half a mile from any subway stop.

About half of the passengers get to or from the airport by taxi, and another 20% are dropped off or picked up in a car. Only 6.2% use public transportation, and another 5.6% use a shared ride such as a hotel shuttle.

Among employees, the situation is different. I expected employees to cluster in western and central Queens, but in fact, based on the same categories used for passengers, the largest group is Queens East beyond subway range:

There are 13,000 employees at LaGuardia per Port Authority (compared with about 10,000 per OnTheMap), of whom 40% take transit to work and 57% drive. It goes without saying that the transit options are exceedingly harsh. The connections from Brooklyn require taking a subway through Manhattan (and I don’t think LGA is necessarily important enough to justify a direct bus route from Brooklyn, presumably a merger of the B38 with a Q18/Q47 compromise route to the airport). From Queens beyond subway range they require taking a bus to the subway and then another bus. The implication is that people take transit to the airport out of necessity – that is, poverty – and not because the options are good.

Unfortunately, the implication is also that it’s hard to serve the current employee base by any rail link, even if it’s fare-integrated with the subway (unlike the JFK AirTrain). The origins are too dispersed. The best that can be done is serving one tranche of origins, and letting passengers sort themselves based on commute possibilities.

In some strategic places, a decent two-seat ride can be made available. The M60 bus is not good for passengers, but it is fine for employees since more of them come from Upper Manhattan and the Bronx, and moreover low incomes imply that it’s fine to have a transit : car trip time ratio well in excess of 1 provided it’s not too onerous. Some future rail extensions, not covered in the study, would help with passenger distribution: Triboro RX would help get passengers from the South Bronx, Brooklyn, and parts of Queens to major transfer points at Astoria and Jackson Heights, and Penn Station Access with an Astoria stop would help get eastern Bronx passengers into Astoria with a quick transfer.

The alternatives analyzed

The study mentions a horde of different options for connecting people to the airport, but most only get a few paragraphs followed by an indication that they don’t meet the objectives and therefore should not be considered further. These excluded alignments exist only for i-dotting and t-crossing, such as ferries or whatever Elon Musk is calling his tunnels this year; Port Authority is right to reject them.

The alternatives proposed for further consideration consist of no build, subway extensions, and various air train alignments. Unfortunately, on second pass, the subway extensions are all eliminated, on the same grounds of community impact. This includes the least impactful subway extension, going north on 31st Street and then east on 19th Avenue, avoiding Ditmars (which could host an el).

Instead of a subway extension, the study is recommending an air train. There are many alternatives analyzed: one from Astoria along the Grand Central Parkway, one from Woodside with a connecting to the local M/R trains on the Queens Boulevard Line at Northern Boulevard, one from Jackson Heights, one from Jamaica with a missed connection to the 7, and one from Willets Point as recommended by Cuomo. All but the last are excluded on the same grounds of impact. Any land acquisition appears to be prohibited, no matter how minor.

What went wrong?

The obvious answer to why the study recommends the Willets Point detour is political support. This can be seen in e.g. PDF-p. 150, a table analyzing each of the air train possibilities. One of the criteria is operational concerns. The Jamaica option fails that test because it is so circuitous it would not get passengers between the airport and either Penn Station or Grand Central in thirty minutes. The Willets Point option passes, despite being circuitous as well (albeit less so); it would still not get passengers to Midtown Manhattan in thirty minutes since the 7 is slow, but the study seems to be assuming passengers would take the LIRR, on the half-hourly Port Washington Branch.

This alone suggests political sandbagging. But by itself it doesn’t explain how the study’s assumptions sandbag the options the governor doesn’t favor; after all, there could be many little omissions and judgment calls.

Rather, I propose that the study specifically looked only at nonstop service to the airport. The subway extensions are all proposed as nonstop services from Astoria (either Astoria Boulevard or Ditmars) to the airport, without intermediate stops. Without intermediate stops, the political will to build els above neighborhood streets is diminished, because few people in Astoria have any need to travel to LaGuardia. In contrast, with intermediate stops, the subway extensions would improve coverage within Astoria, serving Steinway and Hazen Streets.

If intermediate stops are desired, then 19th Avenue may not be the best corridor. Ditmars itself is feasible (with some takings), as are 21st and 20th Avenues. Ditmars has the most impact but serves the highest-value location, and can descend to Grand Central Parkway to get to the airport without any tunneling, limiting costs.

Moreover, the impact of els can be reduced by building them on concrete columns rather than all-steel structures. Paris Metro Line 2 opened in 1903, before the First Subway in New York; it has a steel structure on top of concrete columns, and the noise level is low enough that people can have conversations underneath while a train is passing. New Yorkers should be familiar with the reduced noise of concrete structures since the 7 el on top of Queens Boulevard is quiet, but that is an all-concrete structure on a very wide street; Line 2 here follows wide boulevards as well but not so wide as Queens Boulevard, and is moreover a mixture of concrete and steel, and yet manages not to have the screeching noise New Yorkers are familiar with from Astoria, Woodside, and other neighborhoods with els.

Is this study valuable?

Yes and no. Its conclusions should be tossed for their limited scope (nonstop airport access only), questionable assumptions (overreliance on infrequent commuter rail), and political aims (justifying Cuomo’s decision). But some of the underlying analysis, especially of current travel patterns, is useful for the purposes of thinking about systemwide transit expansion. Despite the consideration of an N/W extension, the study does not try to figure out the percentage of travelers whose ultimate origin or destination is near an N/W stop, only near a 7 stop; however, we can make some educated guesses from the map and realize that an N/W extension is of considerable value to passengers.

For employees, the situation is more delicate. The study mentions them but doesn’t try to optimize for them – the aim is to give Cuomo political cover, not to design the best possible public transit for New York. But the dispersal of worker origins means that a single rail link to the airport is unlikely to have much of an effect. Better everywhere-to-everywhere transit is needed. With decent bus connections at Astoria and Jackson Heights, it’s more important to build circumferential transit there (that is, Triboro) than to connect directly to the airport.

A general program of transit expansion would serve both groups. An N/W extension through Astoria with intermediate stops would give the neighborhood better coverage while also connecting the airport with Manhattan destinations, with good transfers to origins on the Upper East and West Sides. Better circumferential transit would then let workers from different parts of the city use the same extension without having to detour through Midtown even if their origins are in the Bronx or Queens.

Can any of this happen? The answer is unambiguously yes. Even in New York, els and at-grade rail is not so expensive. The only real question is whether good transit can happen while the state is governed by a do-nothing administration, headed by a governor who is more interested in a signature project than in improving transportation for his hapless subjects.

Heterogeneity of Preferences

The public transit conversation is full of statements like “passengers don’t like to transfer,” or, in quantified terms, “passengers perceive a minute transferring to be equivalent to 1.75 minutes on a moving vehicle.” But what does this exactly mean? It’s not a statement that literally every passenger has a transfer penalty factor of 1.75. Different passengers behave differently. At best, it’s a statement that the average passenger on the current system has a transfer penalty factor of 1.75, or alternatively that the aggregate behavior of current passengers can be approximated by a model in which everyone has a transfer penalty factor of 1.75. Understanding that different people have different preferences is critical to both the technical and political aspects of transportation planning.

I talked about the heterogeneity of transfer penalties three years ago, and don’t want to rewrite that post. Instead, I want to talk more broadly about this issue, and how it affects various transit reforms. In many cases, bad American transit practices are the result not of agency incompetence (although that happens in droves) but of preferential treatment for specific groups that have markedly different preferences from the average.

Disabilities

The universal symbol of disability is the wheelchair. Based on this standard, every discussion of accessible to people with disabilities centers people in wheelchairs, or alternatively retirees in walkers (who tend to make sure of the same infrastructure for step-free access).

However, disabilities are far broader, and different conditions lead to dramatically different travel preferences. One paper by the CDC estimates that 20% of US adults have chronic pain, and 8% have high-impact chronic pain, limiting their life in some way. People with chronic pain are disproportionately poor, uneducated, and unemployed, which should not be a surprise as chronic pain makes it hard to work or go to school (in contrast, the one unambiguously inborn socioeconomic factor in the study, race, actually goes the other way – whites have somewhat higher chronic pain rates than blacks and Hispanics). Another paper published by BMJ is a meta-analysis, finding that depending on the study 35-51% of the UK population has chronic pain and 10-14% has moderately to severely disabling chronic pain.

I’ve only talked to a handful of people with chronic pain – all of working age – and the best generalization that I can make is that it is impossible to generalize. The conditions vary too much. Some find it more painful to drive than to take transit, some are the opposite. Some have conditions that make it hard for them to walk, some are fine with walking but can’t stand for very long. To the extent the people I’ve talked to have common features, they a) have a strong preference for rail over bus, and b) require a seat and can’t stand on a moving vehicle for very long.

Work status

The best use case for rapid transit is getting people to work in a congested city center at a busy time of day, ideally rush hour. Off-peak ridership is generally cheaper to serve than peak ridership, but this is true for all modes of transportation, and public transit tends to be relatively better at the peak than cars. Per table 2 of the Hub Bound report, as of 2016, 19% of public transit riders entering the Manhattan core do so between 8 and 9 am and 43% do so between 7 and 10 am, whereas the corresponding proportions for drivers are 6% and 18% respectively.

The upshot is that people are more likely to ride public transit if they work a salaried job. This is especially true in the middle class, which can afford to drive, and whose alternative is to work at some suburban office park where car ownership is mandatory. In the working class, the distribution of jobs is less CBD-centric, but the ability to afford a car is more constrained.

The social groups most likely to drive are then neither the working class (which doesn’t own cars anywhere with even semi-reasonable public transit) nor the professional working class, but other social classes. The petite bourgeoisie is the biggest one: small business owners tend to drive, since they earn enough for it, tend to have jobs that either virtually require driving (e.g. plumbers) or involve storefronts that are rarely located at optimal locations for transit, and need to go in and out at various times of day.

Another group that’s disproportionately likely to drive is retirees. They don’t work, so they don’t use transit for its most important role. They take trips to the hospital (which is bundled with issues of disability), which can be served by buses given that hospitals are major job centers and non-work travel destinations, but their other trips tend to be based on decades of socialization that have evolved haphazardly. The urban transit network isn’t likely to be set up for their particular social use cases.

Consensus for whomst?

I bring up small business owners and retirees because these two groups are especially empowered in local politics. When I lived in Sweden, I could vote in the local and regional elections, where I had no idea what the main issues were and who the candidates were; I voted Green based on the party’s national platform, but for all I know it’s not great on Stockholm-specific issues. Figuring out the national politics is not hard even for a newcomer who doesn’t speak the language – there are enough English-language news sources, there’s social media, there are friends and coworkers. But local politics is a mystery, full of insider information that’s never spelled out explicitly.

What this means is that the groups most empowered in local politics – that is, with the highest turnouts, the most ability to influence others in the same constituency, and the greatest ability to make consistent decisions – are ones that have local social networks and have lived in one place for a long time. This privileges older voters over younger voters, and if anything underprivileges people with disabilities, whose ability to form social and political connections is constrained by where they can go. This also privileges people with less mobile jobs – that is, shopkeepers rather than either the professional middle class or the working class.

With their greater local influence, the most empowered groups ensure the transportation that exists is what is good for them: cars. Public transit is an afterthought, so of course there is no systemwide reorganization – that would require politicians to care about it, which interferes with their ability to satisfy the politically strongest classes. But even individual decisions of how to run transit suffer from the same problem when there is no higher political force (such as a strong civil service or a national political force): bus stops are very close together, transfers are discouraged (“we oppose the principle of interchange” said one left-wing group opposed to Jarrett Walker’s bus redesign in Dublin), rail service is viewed more as a construction nuisance than a critical mobility service, etc.

Models for transportation usage take into account the behavior of the average user – at least the average current user, excluding ones discouraged by poor service. However, the political system takes into account the behavior of the average empowered voter. In the case of local politics, this average voter rarely rides public transit. When city political machines run themselves, the result is exactly what you’d think.

Phased Implementation of Bus Redesign

Jarrett has a good post about the new Auckland bus redesign, which he had been involved in when he worked for international consultancy MRCagney, before he opened his own. He mentions one peculiar aspect of Auckland – namely, that it is so divided by water boundaries that different areas of it have independent surface transit networks – that facilitates gradual implementation. In contrast, in a city with a more connected street network, every route affects every other route, so redesign has to be implemented together, without any intermediate phases. He brings up Brooklyn (together with Queens) as one example of such a connected network, and I feel like I need to explain why a phased approach is appropriate there.

But this is not just about Brooklyn. The question of whether to implement changes abruptly or gradually generalizes to every scale, up to and including the type of regime (democratic, militaristic, communist, etc.). The scope of this post concerns bus networks anywhere. The arguments I bring up in favor of a phased approach in Brooklyn should also give correct answers in other cities, regardless of whether they end up recommending gradualism.

Sharp edges

Jarrett brings up one factor influencing whether phased implementation is appropriate: sharp edges between different parts of the city. In New York, the East River has few road crossings and many rail crossings; only one local bus crosses it in Brooklyn, the half-hourly B39, and only four cross it in Queens.

But even edges that look less sharp than the East River or the Hudson can be so stark so as to permit separate planning on their two sides. The Harlem River is one example: many Bronx buses cross it, but their routes in Manhattan are constrained based on which avenue or street the bridge connects to, so there’s not much scope for creative recombination.

Brooklyn itself has few internal sharp edges. The closest thing to a sharp edge is the combination of Greenwood Cemetery and Prospect Park, separating on one side Park Slope and South Brooklyn and on the other side Flatbush and Southern Brooklyn. A few marginal neighborhoods are sharply divided from the rest of the borough, especially Red Hook. But for those neighborhoods, the question of where in the rest of the borough they should connect to depends on the shape of the rest of the system.

That said, it’s plausible to talk about how the new network would look in various neighborhoods, if there are choke points or generally agreed upon spines. Red Hook is an especially good example, since it has a strong connection to Manhattan via the Brooklyn-Battery Tunnel (hence, our proposed tunnel bus to Lower Manhattan). But as the arguments in comments here over Williamsburg show (and as my constant refrain about the north-south Bed-Stuy routes shows), it’s possible to discuss individual neighborhoods even if they’re more strongly connected, as long as it’s clear that it’s in the context of a greater network.

However, in one aspect, Jarrett and the MTA make a mistake: they treat the edge between Brooklyn and Queens as less sharp than it really is. In the north, the Newtown Creek choke point forces buses to all go up to Long Island City along a single bridge. In the center, a few route mergers passing through Bushwick and Ridgewood (especially the B54/Q55 on Myrtle) are reasonable, but fully integrated planning would not create very many connections. It’s possible to design the network for Brooklyn alone and then notate where Queens connections would happen, just as it’s possible to design a Manhattan network and point out that the M60 goes into Queens.

The subtle issue regarding Brooklyn and Queens concerns what happens in the south. At TransitCenter we were asked about connections to Howard Beach, but when I looked, I ran across a subtle geographic divide. The southeastern margin of Brooklyn and Queens is a series of small peninsulas with weak connections between them: Gerritsen Beach, Mill Basin, Bergen Beach, Canarsie, Starrett City, Spring Creek, Howard Beach, Old Howard Beach. When I crayoned a metro network for Lagos, which has the same problem in the west and northwest, I had to assume new metro bridges connecting various neighborhoods. On a surface transit network in a developed country, such bridges are unlikely to happen, forcing buses to use the main through-routes today, like Flatlands and Linden.

Is it good enough today?

The entire reform versus revolution discourse depends on how bad things are today. It’s unavoidable in discussions of socialism and Marxism. Socialists and even some social democrats hold that mid-20th century social reforms (like the New Deal) saved capitalism from itself, by making the working class’s situation less desperate. As a result, there is a contingent of leftists who call themselves accelerationists, who prefer to make things as bad as they can be (for example, by refusing to back the center-left against the far right) hoping that this would accelerate the revolution.

The “is it good enough today?” principle scales down to any level. When it comes to bus networks, it really asks, how much would the optimal route network differ from today’s situation?

The highly radial buses of San Jose today, Houston before Jarrett’s redesign, and Barcelona before Nova Xarxa all differ greatly from the redesigned networks. This encourages abrupt implementation, in two ways. First, the old routes are generally weak, increasing the pressure to get rid of them. And second, the old routes don’t feed the new grid trunk lines well, whereas the grid trunks feed one another. Nova Xarxa (which is a six-year process, retaining many old lines) has seen its phase 1 lines grow in ridership as each subsequent phase was implemented, making the early stages much less useful than the entire system.

In contrast, Brooklyn is firmly in the good enough basket. This does not mean its current network design is objectively good; it isn’t. But it does mean that most of its key trunk lines should survive redesign with at most light modifications. Among the 15 busiest Brooklyn routes today measured by ridership per km, only three see big changes: the B1 (straightened into a Southern Brooklyn grid), the B82 (cut to Kings Highway, its tails on both sides given to the B6), and the B41 (cut north of the B/Q subway connection at Parkside). A few more are merged into longer routes, like the B42 and the B60, but maintain their current route, just with through-service elsewhere. Key grid routes like Lafayette, Church, Nostrand, Avenue M, and Myrtle survive almost unchanged.

The Brooklyn redesign is not predominantly about starting from scratch, since the network today already has the characteristics of an imperfect grid. It’s about consolidating weak and weak-ish routes, straightening some buses that are too circuitous, and switching around buses to serve destinations that have grown stronger since the 1970s redesign. The East New York network in particular has a lot of meanders that should be fixed regardless of what happens anywhere else; the rest of the bus and subway network is good enough that people from East New York can then transfer to it even if increasing trunk frequency happens later.

Future changes

Bus redesigns are not immutable, to be done once in a few decades with long periods of stasis in between. Cities change, and the optimal bus network for 2025 may be different from that for 2019 in some situations. In a city where there’s relative stasis in development intensity, traffic, and any rail trunk, an abrupt change makes more sense. Realistically, such a change would come not when the first phase of a gradual implementation would have been done but when the middle or last phases would have. Thus, if the redesign is a long-lasting product it’s easier to wait for the first phase (which in an abrupt implementation is also the last phase) and not change much afterward.

This relates to California Transit Twitter’s biggest criticism of Jarrett’s San Jose redesign: that it does not incorporate the recent BART extension to Warm Springs. Jarrett unveiled his redesign for VTA in the spring of 2017, expecting BART to be extended from Warm Springs to the San Jose Flea Market at Berryessa by the end of the year, as BART had projected. Based on this expectation, he designed the network around an abrupt implementation, to go into effect shortly after trains would start running to Berryessa. Since then, BART has announced delays to the extension, talking about opening it only at the end of 2019. Trusting BART’s early promises of 2017 opening is an understandable error; Jarrett did not cause the BART timetable slip. But the outcome is that the VTA bus redesign is delayed.

The upshot is that in a city with a rapidly-growing rapid transit network, bus redesigns should be done on a continuous basis, tweaked every time a new subway line opens. The Bay Area is not generally such a city, but BART is expanding into San Jose, so in that part of the region, phased implementation with updates every few years is warranted. By the same principle, a city with rapid changes in where people live and work should expect recurrent changes to its surface transit network; this is less relevant to San Jose, since the growth nodes are the CBD (e.g. the upcoming Google building) and the Apple headquarters in Cupertino, but it’s relevant to cities in which residential areas are commercializing, such as San Francisco with SoMa.

New York, of course, has a static subway system, courtesy of extreme construction costs. It also has a relatively static workplace geography. However, in one respect, it is undergoing rapid change: it is gradually making its subway network accessible. When I say that the optimal networks for 2018, 2022, and 2026 are all different, I say this in reference to upcoming subway accessibility upgrades, as well as potential changes (i.e. de-interlining) that would increase subway frequency at the cost of one-seat rides. In Brooklyn, our plan to get rid of the B25 depends on upcoming accessibility upgrades for Broadway Junction, without which the bus should probably stay as an accessible alternative to the A and C trains. Likewise, our plan to retain the B63 comes from plans to only make the outermost R stations accessible but not the ones in Sunset Park or South Slope.

What about Nova Xarxa?

On two out of three metrics, Barcelona’s layout recommends an abrupt approach: it lacks internal sharp edges, and its preexisting network was too radial to be useful. On the third, it does not: it is rapidly expanding its metro network; however, the implementation of Nova Xarxa as far as I can tell has not been timed for the opening of L9/L10. So why is it phased there?

The fact that the early-phase lines of the network have seen further increases in ridership as the rest of the network has come online suggests that, on purely technical criteria, gradual implementation was not the right choice in Barcelona. However, in political reality, Nova Xarxa could not replace the entire radial network. Most bus routes in Barcelona today are still not Nova Xarxa. The system’s characteristic as an overlay that took over old lines that became superfluous forced it to be done in phases.

Conflicting excuses

In comments, people here have warned that a phased implementation can be an excuse to do nothing: put the few things everyone agrees on in the first phase, do that, and then postpone future phases indefinitely. This is a real risk. However, abrupt change has its own risks as well: it can be used as an excuse not to do low-cost or negative-cost things that can be implemented fast, such as merging the two Myrtle routes, redoing the East New York bus network in advance of the L train shutdown, and opening the Red Hook-Lower Manhattan route.

The upshot is that the question of gradualism seems independent from the question of obstructive bureaucrats and apparatchiks. There may well arise a local situation in which one answer to the main question is less vulnerable to political sabotage than the other, but it depends on idiosyncratic factors and is unlikely to be the case in general.

With the political criteria uncertain, the answer to whether network redesign should be done in one go or in stages should depend only on technical criteria. These differ from city to city and from region to region depending on local physical and urban geography. In New York, they suggest a phased implementation would work; elsewhere, they may not.

Brooklyn Bus Redesign Version 1.2

About two weeks ago, Eric Goldwyn and I unveiled our Brooklyn bus redesign. It consolidates the borough from 550 route-km to about 350, and cuts the number of stops along the surviving lines from 1580 to 706; the increase in speed coming from stop consolidation and other treatments (i.e. bus lanes and prepayment) and the route consolidation together permit doubling the frequency with the same resources available today, guaranteeing that each bus route have at worst 6-minute frequency between 6 am and 10 pm. The first version we released was 1.0, and the version I blogged was 1.1. In this post I’d like to introduce changes as well as explain why we made certain decisions that have been criticized in comments here and elsewhere.

Version 1.2

V1.2 differs from v1.1 in just two ways. First, it was pointed out to me that we made a mistake in the map: the route we proposed for the B6 to take across the structure of the Brighton Line of the subway, at Avenue H, was not in fact a street crossing. At Avenue H the structure goes from trenched to the north to elevated in the south, and as a result the street does not go through. We fixed this error by restoring the present-day route, and also slightly changing the route of the B11 to follow what must be a high-quality bus lane.

And second, months ago, in arguments with former MTA planner Allan Rosen (who comments on blogs by the name BrooklynBus and has his own proposed redesign), there came the question of the route of the B9. Allan was supportive of the idea of running the B9 on Veterans Avenue, taking over what is now a B41 branch, rather than going to Kings Plaza as it does today, legacy of an era when Kings Plaza was a more important shopping destination. I also asked about straightening the route, which currently goes on a combination of Avenues L and M; Avenue M provides a straighter route connecting to the important destinations (the eastern end of the route, and the main drag in Midwood at Avenue M). Allan explained that no, a reroute to Avenue M is not feasible, as east of the heart of Midwood it’s a narrower residential street, forcing the bus to use the wider Avenue L. The only reason the straighter Avenue M route appeared on v1.0 and v1.1 is that I forgot to change it; after we went public with the map, he reminded us.

There are some associated changes to the stop spacing to accommodate the new routes (or, rather, the retention of old routes that we were wrong to try to change before), but overall there is practically no impact on overall trip times. The B9 is a few hundred meters longer than in v1.0 and v1.1, but the cost in on the order of 20 service-hours per weekday, which by itself is a lot lower than my uncertainty in the underlying numbers (which is about 100 hours).

Service-hours vs. fleet requirement

When putting together the redesign, we aimed at one cost metric: service-hours. This is the correct metric for variable bus operating costs, as they are dominated by the driver’s wage (which is hourly, not per km) and to a lesser extent maintenance costs (which are partly distance-based and partly time-based, as the frequent acceleration cycles common to slow bus traffic stress the engine). The MTA costs buses by distance and not time, which is not a bad approximation when all buses are about equally fast, but generates wrong results when the subject of the discussion is speeding up the buses, as we propose.

But there’s one more metric we did not consider: fleet requirement. Our redesign actually saves money there, which should not be a surprise, as it has more off-peak service, which implies less service at the peak. Our 10,000-hour schedule requires a fleet of 1,007 buses, which compares with 1,129 today excluding the MTA Bus-operated B100 and B103 (which look like they require about 40 vehicles between them). Our proposed v1.2 schedule has 7.5% fewer service-hours than today – not because we propose a cut but because we expect future additions and politicized slowdowns to add hours – but 14% fewer buses. The smaller fleet is to be used more intensively and somewhat more efficiently thanks to the removal of short, infrequent routes.

Since the goal is to keep the redesign roughly cost-neutral, it’s likely that overall service-hour figures will rise: higher operating costs will be balanced by slightly lower capital costs, as the MTA will need to procure slightly fewer buses and not need to expand depots for them as much. In 2008-11, the MTA spent $500,000 per bus on procurement; in 2014, this was the cost per standard bus (which is the vast majority of the MTA Bus and NYCT fleet), while articulated buses were $750,000. This is a premium of about 50% over London bus costs.

Overall the fleet requirement looks like a small proportion of the cost. A $500,000 bus, say $600,000 at today’s higher prices, operates for 12 years, and requires a team of about five drivers, each earning around $140,000 a year with benefits. This is just about market wage – San Francisco and Boston, which pay about the same, have trouble finding and retaining drivers; high bus driver wages should be viewed as similar to high wages for oil rig workers, compensating for poor work conditions. Excluding the costs of depot enlargement, the overall exchange rate seems to be about one bus = 40-45 daily service-minutes. At best, our redesign can squeeze maybe 100 extra daily hours out of better fleet utilization.

The Williamsburg issue

As Eric and I have always emphasized in our communications, our redesign is necessarily win-lose – it’s just that there’s overall much more winning than losing. This is true across neighborhoods as well as within neighborhoods. The diciest case is that of Williamsburg, where we are proposing to consolidate a number of routes into 1.5 north-south trunk lines: one is a continuation of the B44 running up Bedford, and the other goes up Graham and thence either Manhattan Avenue (connecting to the G) or McGuinness (a straighter route on a wider street). This guts service to South Williamsburg, especially west of the BQE, where the only remaining stops are the Marcy Avenue J/M/Z subway stop and another stop on Broadway at Bedford.

It’s not an optimal situation. However, it’s a necessary cut, for a number of reasons:

  1. The existing north-south lines in Williamsburg are for the most part quite weak. The average weekday ridership per route-km in Brooklyn is about 1,100. The Williamsburg routes are at 945 (B43), 613 (B62), 414 (B67), 358 (B48), 225 (B24), and 152 (B32). The strongest two run along the routes that we are retaining for north-south service, but the rest are so weak that consolidation is required; for the same reason, we are replacing the B48 and B69 (which is at 453) in Clinton Hill with a compromise route on Washington.
  2. The Williamsburg routes are not just weak but also wasteful, measured in ridership per service-hour. Borough average is 55, and the overall strong routes cluster in the 60s, with high ridership balanced by high service. The top three routes are the B74 (98), B1 (82), and B36 (70), serving short-hop trips in Southern Brooklyn. Among the Williamsburg, only the B43 (49) holds up; the B62 (42), B67 (39), B32 (35), B24 (35), and B48 (32) are weak, the last three all falling in the borough’s bottom six.
  3. The main north-south route in South Williamsburg west of the BQE is Bedford. Unfortunately, a continuous route up Bedford misses the all-important connection to the subway at Marcy. The B62 resolves this issue by detouring to serve Marcy, which slows down through-riders.
  4. Williamsburg streets are narrow. Even Bedford is only 18 meters wide, comparable to a Manhattan street. Bus speeds are unlikely to be high in such a situation, and bus lanes are guaranteed to be contentious due to the removal of on-street parking and loading access.
  5. The eastern margins of Williamsburg and Greenpoint are awkwardly just too far away for some people to walk to the subway (Meeker Avenue’s easternmost residential area, at Van Dam, is 960 meters from the nearest bus stop in our plan and 1,370 from the G train), but just close enough that most people will still walk rather than take a bus unless the bus is extremely frequent. Without the travel intensity found in Coney Island and at Kingsborough Community College, there is no hope for the travel volumes justifying very high frequency on the routes there, especially the B1. A frequency-ridership spiral is unavoidable, helping explain the poor performance of the B24 and B48.

The only possible compromise is to keep the B44’s current route on Lee, which in our plan we slightly straightened to reach the Marcy subway station faster. Keeping the northbound direction on Bedford, which serves South Williamsburg more centrally than Lee, is out of the question: south of Flushing Avenue, Nostrand is unambiguously more important, and the northern tail of the B44 is too weak to be allowed to drive the placement of the entire route. The cost of restoring the Lee/Taylor bus stop is small, around 12 daily service-hours, and this can be incorporated into the next version. However, it still only serves the area peripherally, and slows through-riders by around 1.5 minutes each way.

Brooklyn-Queens connections

People have told us that interborough connections are the new hot thing, to replace the borough-by-borough bus planning that currently exists. We are not depicting any on our map beyond what currently exists: one route to JFK, the aforementioned north-south Williamsburg route to Long Island City, and a bunch of east-west routes through Bed-Stuy terminating slightly east of the borough line. We are willing to be convinced otherwise, but so far it seems like adding more connections is difficult, for several unrelated reasons.

Hard boundaries

The Brooklyn-Queens border may not be as stark as the East River or the Harlem River, but it is nonetheless mostly hard. East of the Greenpoint/LIC border, the border follows a polluted industrial creek; the B24 crosses it twice and is very weak, and there’s no good route until the cluster of Grand, Metropolitan, and Flushing around Ridgewood. Metropolitan and Grand do go through, and we indicate them on our map. Flushing doesn’t; there’s no good route in Queens to connect it to except maybe a hybrid of the Q18 and Q47 to LaGuardia, and even that is uncertain.

Beyond Ridgewood, there is another hard boundary consisting of several cemeteries. The B13 goes through today, but is a weak route (473 riders/km, 38/hour) and should be cut to just a north-south subway feeder. To the immediate south of the cemeteries, several Queens buses go through to key connection points in Brooklyn. Only the southernmost zone, around Howard Beach, has weak connections.

Queens is not Brooklyn

Brooklyn is relatively uniformly dense, making a grid with uniformly high frequency tenable. Queens is not. East Elmhurst is several times denser than Queens Village. Central and Eastern Queens have a street hierarchy, in which the list of which streets get bus routes is preordained: Lefferts, Jamaica, Union Turnpike, Main, etc.; it’s not the relatively flat grid hierarchy that characterizes most of Brooklyn. There are multiple town centers to serve, with too sparse a rail network for buses to work purely as a rail feeder. The LIRR has so many stations that there are two distinct optimal maps, one assuming fare and schedule integration with commuter rail and one assuming today’s lack of integration.

What this means is that maybe a uniform 6-minute frequency is not right for Queens. Maybe the larger geographic size of Queens, with longer bus routes, permits slightly lower frequency, say every 8 minutes at the base (maybe even every 10). Combining routes is not always the right approach in this situation; there are going to be frequency-based seams.

Depot locations

There are some potential combinations of Brooklyn and Queens bus routes, most obviously on Avenue, which hosts the B54 and Q55. The B12 could even be combined with the Q56 and Q24 as branches. The Q58, an extremely strong circumferential, could be combined with the B38, the busiest Brooklyn route near its terminus. The problem is that the break points today tend to be very close to bus depots, and often they’re major destinations in their own right, such as the subway connection point at Broadway Junction or at Myrtle/Wyckhoff.

The B54/Q55 combination seems relatively easy, but the rest are more strained. At East New York Depot especially the loss of the easy pullout is unlikely to justify cutting the transfer to the few through-riders.

The City Line problem

At TransitCenter, we were asked specifically about the southernmost part of the Brooklyn/Queens border, covering City Line and Spring Creek on the Brooklyn side and Lindenwood and Howard Beach on the Queens side. The bus network there today is glaring in its gaps: there is no east-west connection south of the Q7 (the B15 looks like a connection on a map, but runs nonstop from Brooklyn to JFK). The street network itself is poorly connected, but even the existing connection at Linden doesn’t host local buses.

And yet, there’s not much room for serious improvements. The B15 could make a stop just over the border on the Queens side, but its route to the airport takes it through a highway with nowhere to stop; a BRT lane with some stops at north-south arteries like Woodhaven might be possible, but would not be a pleasant place to transfer at.

Worse, going on Linden and then southeast toward Howard Beach raises a difficult question: where does such a route go on the Brooklyn side? There are too many options: Gateway Center, New Lots on the 3, Euclid on the A/C. Reverse-branching is out of the question. Of those, probably the best is New Lots – Euclid serves a subway line that Howard Beach can get to more easily without the bus, and Gateway will always be too circuitous compared with driving on the Belt Parkway.

Tweaks vs. redesign

There are tweaks that improve Brooklyn-Queens connectivity, like merging the two Myrtle routes, giving the Brooklyn-JFK route dedicated lanes to facilitate a stop at Woodhaven, and changing the Metropolitan and Grand routes slightly to improve intra-Williamsburg east-west service (already depicted on our map). However, this is not the same as a redesign. In some parts of Brooklyn our proposal is a tweak, for example the east-west routes in Bed-Stuy, but in Southern Brooklyn and East New York we are rationalizing nearly everything into a grid, and in Bushwick and Canarsie we are proposing extensive changes.

Additional routes?

Based on the shape of our proposal, there are a few potential additions. One involves a 16th Avenue north-south route, possibly veering east to follow Cortelyou and Beverly. Another involves an Ocean Parkway bus to Church. A third involves extending the B17 up through Bed-Stuy to provide a second interpolating route between Nostrand and Malcolm X, which is available today (as the B15 and B43) but not on our map. A fourth involves going up Smith Street between Red Hook and Downtown Brooklyn until the subway stops in South Brooklyn are made wheelchair-accessible.

However, all of those add a hefty number of service-hours. Whether they’re tenable depends on how strictly NYC DOT implements our recommendations for dedicated lanes on every bus route. If no bus routes are added on top of the ones that exist today, v1.2 requires 11,050 revenue-hours and 1108 buses. This is still more or less achievable with current resources (it requires about a 1-1.5% increase in costs), but there is no room for any additional routes, or for restoring the B25. And that’s without taking into account compromises on bus stop spacing and bus route reliability.

In contrast, things are rosier if the reliability improvements we prescribe are implemented, and if every bus that needs a dedicated lane (i.e. nearly all of them) gets it even if motorists complain. There’s room in the budget for additional service. The above bus routes, excluding B25 restoration, total about 30 km including some possible tie-ins elsewhere in the system, creating nearly 800 new service-hours, bringing the system to the same place it is today, maybe just 1% short given additional efficiency and fleet savings.

And if higher ridership brings in more revenue for the same expense, there should be room for more service increases. The network in v1.2 could support maximum 5-minute peak headways on all routes for 210 more hours, which should not be hard to accommodate even with more routes. Going down to 4-minute peak headways requires another 370 hours, and going to 5-minute off-peak headways requires another 890.

To do all of this, another 1,300 hours or so are needed net of efficiency gains. To keep the subsidy per rider constant, this requires a 12% gain in overall linked trips, which isn’t outlandish (it would still leave Brooklyn with less bus ridership than at the 2002 peak). Making such expansion cost-neutral is harder: a linked trip nets about $2 in revenue, and this expansion would cost about $95 million annually, and then the required growth in ridership, 47.5 million, is 25% over Brooklyn’s unlinked bus ridership. It still looks achievable but very ambitious, relying on a positive frequency-ridership spiral.

Will this happen?

Some variant of a bus redesign will definitely happen. It’s in vogue in the US right now, and the MTA is taking this as an excuse to rationalize its bus service, which has accumulated a lot of oddities and historical artifacts that no longer make much sense.

The question is, will a good redesign happen? That I don’t know. I believe our redesign is good. The conversations I’ve had with bus planners at the MTA have been positive and suggest to me that, barring political interference, they are likely to come up with good redesigns as well, sharing the same overall characteristics as ours. We are working from the same set of best practices, for the most part.

But then the political question looms large. Physically separated bus lanes and signal priority require the city to give a damn about bus riders. Stop consolidation requires the MTA to stick to a long interstation even if minority of people who are hurt by it (e.g. by having high walk penalties and low wait penalties) complain. All of this requires political appointees at DOT and the MTA to consciously think how they can provide better public transit to the city they serve. Will they deliver?

Our Brooklyn Bus Redesign

Eric Goldwyn and I spent about six months working on a Brooklyn bus redesign. I mentioned some aspects of it before here, on social media, and in blog comments, but not the overall shape. Eric and I gave a pair of presentations about our plan, one two days ago at the MTA in front of senior MTA planners and NYC DOT people and one today at TransitCenter in front of activists and mid-level MTA planners. We have a still-unreleased writeup explaining everything we’re doing with references to both public reports from various cities and peer-reviewed literature. Here I’m going to condense the 8,000-word writeup into a blog post length, going over the main points, including of course the proposed map.

The map, in brief

The depicted version is 1.1. You can see a lower-resolution version 1.0 on Streetsblog, albeit with a different color code (the map we made for the presentation, reproduced on Streetsblog, uses red for the highest-frequency routes and blue for the lowest-frequency ones whereas the Google Earth version linked above is the opposite). It has 353 route-km, down from about 550 today, not including Grand and Metropolitan Avenues, which are Queens bus routes, shown on the map for completeness’s sake, without stopping pattern.

Some tails are cut due to low ridership or duplication of rail:

  • The B25 on Fulton goes.
  • The B37 on Third Avenue is consolidated into the B63 on Fifth.
  • The B45 and B65 are merged into one compromise route.
  • The B15 is cut east of the Long-Term Parking JFK AirTrain station (where service is free); ideally it would be cut east of City Line with passengers taking the subway to the AirTrain (as was the case in version 1.0), but I do not expect Port Authority to integrate AirTrain fares with the subway.
  • The B41 is cut north of Parkside Avenue, at the transfer to the B/Q.
  • Instead of two routes in Bed-Stuy between Nostrand (i.e. B44) and Malcolm X (i.e. B46), today’s B15 and B43, there’s just one route.
  • The B57 segment on Court and Smith Streets in South Brooklyn goes, as the subway serves the area in several directions.
  • The B39 over the Williamsburg Bridge goes.
  • The B32 and B62, providing north-south service through Williamsburg up to Long Island City, are merged into one compromise route.
  • The East New York bus network is circuitous (buses go to Gateway Center the long way around) and is straightened here.
  • In version 1.0, the B26 on Halsey was cut west of Franklin with a forced transfer to the subway, but the short distance to Downtown Brooklyn argues in favor of continuing to at least Flatbush.

Overall, this is a cut from 54 routes (including the separately-managed MTA Bus routes B100 and B103) to 37. The smaller network is far more frequent. The minimum frequency is,

  • Every 6 minutes between 6 am and 10 pm every day.
  • Every 10 minutes between 5 and 6 am and between 10 pm and midnight.
  • Every 30 minutes between midnight and 5 am; every 20 minutes with timed transfers to the subway is aspirational, but the subway doesn’t run reliably on a timetable overnight for such a system to be viable. The 30-minute night network could potentially involve mini-pulses in Downtown Brooklyn and smaller hubs (like East New York and Bay Ridge).

Routes depicted in red on the Google Maps link, or in blue on the map in the Streetsblog link, have exactly the minimum frequency. Routes depicted in green have higher frequency at the peak; routes depicted in blue on Google Maps or red on Streetsblog have higher frequency peak and off-peak. Higher frequency than the minimum is depicted as “Utica [2/4]” (buses on Utica run every 2 minutes peak, 4 off-peak) or “Avenue U [5/6]” (buses on Avenue U run every 5 minutes peak, 6 off-peak). Peak means 7-9 am and 5-7 pm on weekdays, in both directions; the morning peak is a little earlier and the afternoon peak a little later than the subway peak, but as buses are still mostly subway feeders, an earlier morning peak and a later afternoon peak are justifiable.

Speedup treatments

Pruning the network is not the only or even most important part of bus reform. Buses have to be sped up to be useful for people except as last-resort transit. In interviews about unrelated topics, people have volunteered to me that they do not take trips they used to take due to the degradation in bus speed and reliability. New York City Transit bus ridership peaked in 2002; the fare hike in 2003 led to a small dip in ridership that the mid-2000s oil crisis didn’t quite erase, and then in the recession and subsequent recovery bus ridership crashed. In Manhattan it’s 30% below the 2007 level; in Brooklyn it’s 20% below the 2007 level, with buses extending the subway or letting people connect to a better line (like the B41 and B35) particularly hit.

The current average speed in Brooklyn is about 11 km/h. Excluding limited-stop buses, it’s 10.8. We’re proposing to increase it to 15, even though the redesign is pruning buses in faster areas more than in slower ones. This is using four speedup treatments.

Prepayment

Today, New York prefers to treat off-board fare collection as a special product available only on select buses (i.e. SBS). This should be changed to citywide prepayment, with all-door boarding. German-speaking cities do it; so does San Francisco. Data from San Francisco and from the TRB (PDF-p. 20) suggests a gain of about 2.5-3 seconds per passenger boarding, counting both boarding and alighting time. At Brooklyn’s bus ridership level, this suggests a saving of around 400-450 revenue-hours, or about 4% of total service-hours. This is not a big change, but it helps stabilize the schedule by slowing down the mechanism by which buses bunch.

How to get passengers to pay if not on-board remains an open question; there are several approaches. The Zurich model involves placing a ticket-vending machine (TVM) at every bus stop. While New York severely pays for TVMs on SBS (the RPA says $75,000 per stop), an ATM costs $3,000, so installing the required infrastructure need not cost a lot. But more commonly, passengers can board freely if they have transfers or unlimited monthlies and pay the driver (potentially after the bus has begun moving) otherwise.

Of note, the bus drivers are particularly interested in prepayment. Eric and I explained the issue in a CityLab article a few months back: the drivers are worried about being assaulted by riders who don’t want to pay.

Stop consolidation

About 60% of the time saving in our plan relative to current practices comes from stop consolidation. I discussed the issue here, and our forthcoming report has references to many studies in the literature optimizing stop spacing for minimum door-to-door travel time. With each deleted stop saving 20-30 seconds (say 25 seconds on average), our proposed stop consolidation, from an average of 220 meters to 490 excluding long tails (i.e. the B15’s long nonstop segment toward JFK) saves around a minute per km, cutting travel time from 5.5 minutes per km to 4.5.

Conceptually, stop spacing should be longer when trips are longer, or when relative density is less uniform. New York City Transit bus trips are short, as many are subway extenders, but relative density is extremely spiky, as a large number of people get off at a few dominant stops at the subway connection points. If the on/off density on a route is uniform, then lengthening the stop spacing means passengers have to walk longer at both ends; but if passengers are guaranteed a connection at one end (because of transfer points with the subway or other buses) then they only have to walk longer at the other end. Based on this principle, Utica and Nostrand get particularly long stop spacing. Conversely, routes with extremely short trips, like the Mermaid route inherited from the B74, have shorter stop spacing.

To improve network legibility, we have tried as far as possible to have buses stop on consistent streets. For example, south of Fulton Street (where it’s awkwardly between Nostrand and Franklin), Bedford Avenue gets a stop on every intersecting bus, including east-west routes but also the diagonal B41.

Every bus stop should have shelter. In Central Florida, North Florida, and London, this costs $10,000 per stop, give or take. Our 707-stop plan (700 in version 1.0) would cost $14 million at this cost. Even at Santa Ana’s higher cost of $35,000, it’s $50 million. NIMBYs who oppose stop consolidation argue that having many stops is necessary for people with disabilities, but people with disabilities would benefit from benches and shelter, without needing to stand for 15 minutes waiting for bunched buses.

Bus lanes

Every bus in an area with congestion should get dedicated lanes. SBS implementations so far, imperfect as they are, have saved around 30 seconds per km in traffic. Physically-separated median lanes should do better; the MTA and NYCDOT have so far avoided them on the theory that local and limited bus routes should coexist on the same route and limiteds should pass locals, but in reality, a single stopping pattern is better, and then there are no drawbacks to physical separation.

On wide streets, this is not a problem. On narrow ones, it is. The real headache is Nostrand, about 25 meters wide building to building, enough for just four lanes. The correct thing to do is a moving lane and a bus lane in each direction, with merchants told to park on side streets. If parking is unavoidable, then a contraflow bus lane, with parking on one side, is also feasible, but less safe for pedestrians (Boulevard Saint-Michel has this configuration and has to remind pedestrians crossing the street to look left).

Two-way buses are essential whenever streets are widely separated, as on avenues, in Brooklyn as well as Manhattan. Nostrand is just more important than Rogers and New York Avenue, where northbound B44s go today; today’s configuration forces east-west buses to make too many stops (the B35 limited makes 4 stops in a kilometer).

Signal priority

Buses should get priority at intersections and not just on the street. The studies we’ve seen find a 4-7% gain, bus only on individual bus routes, not gridded networks. In our proposed trip times we are not assuming any speedup from signal priority, just better timekeeping as more delayed buses get priority to stabilize the schedule. This is a counter-bunching mechanism more than a straight speedup.

A process, not an immutable product

Jarrett Walker’s bus network redesigns tend to come as complete products, changed rapidly from radial low-frequency networks. What we’re proposing is a longer process. Nova Xarxa began implementation in 2012 and is wrapping up now, installing a few routes at a time by cannibalizing parallel routes. The map we’re showing is what we estimate would be a good fit for 2022-3. Beyond that, more subway stops are going to be wheelchair-accessible, making it easier to prune more subway-parallel buses (like the B63).

Gradual implementation means starting from the easier parts of the network. East New York’s current network is so circuitous that straightening it should not be too controversial. Our proposed redesign there is also better at connecting to the 2, 3, 4, and 5 trains and not just the L, which should prove valuable during the L shutdown. In Southern Brooklyn, we are proposing more service, but this could be paired with stop consolidation. Central Brooklyn and Bed-Stuy require the most street redesigns and the most robust frequency network-wide (as they are already transfer-based grids, and nobody transfers at 12-15 minute off-peak frequency) and could be done later; the B25 itself should probably not be eliminated until Broadway Junction is made accessible on the A and C lines.

We are not even wedded to the map as a proposal for 2022. Some variations are always possible, as already seen in the differences between versions 1.0 and 1.1. The biggest addition we can think of is adding a second north-south route through Bed-Stuy: the existing one would be moved from Marcus Garvey to Throop (hitting the subway better), while the B17 could be extended up Troy and Lewis.

Overall, Brooklyn has 10,800 service-hours today. Our redesign uses just 10,000, with a 1% gain in efficiency from location relative to bus depots on top of that. There is room for service increases, or restoration of marginal routes required for political reasons, or slowdowns imposed by political unwillingness to install bus lanes.

Win-lose

In a modern developed country, it’s rare to find win-win situations. The US is blessed with these in transit (i.e. it’s so inefficient at construction it might as well be third-world), but not in urban bus networks. Stop consolidation is a net benefit to the average user of the route, but a few people would still see longer trips, e.g. those living at the exact midpoint between two widely-spaced stops. Route consolidation (as in Ocean Hill) is the same thing.

There are sociopolitical groups that would win out: labor would see higher ridership, reducing the pressure to cut jobs; regular commuters (who generally have low transfer penalties) would see faster trips; people with disabilities that make it difficult for them to stand (as is true of some people with chronic pain) would be able to sit at bus stops and wouldn’t need to sit for long. In contrast, small business owners would sometimes lose the ability to park in front of their stores, and occasional users who usually drive would see longer perceived trips because of stiff transfer penalties.

This is equally true on the level of neighborhoods. Southern Brooklyn generally gains, and Borough Park in general gains an extra north-south route (though this is canceled out by high transfer and access penalty among Haredis: in Israel they just won’t walk longer to better service). East New York sees much more direct routes. Flatbush and East Flatbush don’t see much change in network structure but do gain off-peak frequency. Red Hook gains a direct connection to Manhattan. But then Bed-Stuy loses north-south routes, South Brooklyn’s buses are completely gutted, and Williamsburg loses north-south routes.

A political system based on citywide (or nationwide) ideological groups could find the will to build the network we’re proposing or something like it. Could a system based on local representation, treating retirees and small business owners as a vanguard class, deliver the same? We will see in the next year or two.

Is Missing Middle Really Missing?

There’s en emerging concept within North American urbanism and planning called missing middle. This refers to housing density that’s higher than suburban single-family housing but lower than urban mid- and high-rise buildings. The context is that in some cities with rapid housing construction, especially Toronto, the zoning code is either single-family or high-density, with nothing in between. The idea of allowing more missing middle housing has become a mainstay of New Urbanism as well as most North American YIMBY movements, underpinning demands such as the abolition of single-family zoning in California and Seattle.

Unfortunately, it’s an overrated concept. It applies to Toronto, but not Vancouver or the most expensive American cities, which are replete with missing middle density. The most in-demand neighborhoods have far too many people who want to move in to make do with this density level. Moreover, missing middle density in its New Urbanist form is not even really transit-oriented: low-rise construction spread over a large area is unlikely to lead middle-class workers to take transit when cars are available. The density required to encourage transit ridership and reduce housing costs is much higher, including mid- and high-rise residences.

What’s missing middle density?

A website created by Opticos Design, an architecture firm specializing in this kind of housing, has a helpful graphical definition:

Many of the missing middle housing forms are part of the vernacular architecture of American cities. In New England, this is the triple-decker, a three-story building with an apartment per floor. In Chicago, this is the fourplex, a two-story building with two apartments per floor. In Los Angeles this is the dingbat, with two or three inhabited floors on top of ground floor parking. In Baltimore and Philadelphia (and in London) this is the rowhouse. This history makes it easier to accept such buildings as both part of the local culture and as affordable to the lower middle class.

The triple-deckers in the parts of Providence and Cambridge I am most familiar with have a floor area ratio of about 1-1.5: they have 2.5 to 3 floors (counting sloped roofs as half a floor) and build on one third to one half the lot. A quick look at some Philadelphia rowhouses suggests they, too, have a floor area ratio in that range. Somerville has a population density just short of 7,000 people per km^2, with little non-residential land and some mid-rise and single-family areas canceling out to missing middle density. Kew Gardens Hills has about 12,000 people per km^2, and has a mixture of missing middle and mid-rise housing.

In Continental Europe, the vernacular architecture is instead mid-rise. In Scandinavia and Central Europe the euroblock has 4-7 floors and a floor area ratio of 2.5-4; Urban Kchoze shows many examples with photos, mostly from Prague, and Old Urbanist finds a euroblock in Berlin with a floor area ratio of 4.3. Central Stockholm’s residential buildings are almost entirely euroblocks, and residential density is 17,000/km^2 in Södermalm, 21,000/km^2 in Vasastan, and 28,000/km^2 in Östermalm. Parisian density is even higher – the floor area ratio of the traditional buildings looks like 4-5, with about 30,000-40,000 people per km^2.

Is missing middle really missing?

In Europe the answer is obviously no: lower-density cities like London are largely missing middle in their inner areas, and higher-density ones like Paris have missing middle density in their outer areas. But even in North America, where the term is popular, the expensive cities where people call for abolishing single-family zoning have missing middle housing. In addition to the above-listed vernacular examples, New York has brownstones all over Brooklyn (the term Brownstone Brooklyn refers to the gentrified inner neighborhoods, but this density is also seen in outer neighborhoods like Bay Ridge and Sheepshead Bay).

Vancouver is an especially instructive example. English Canada’s big cities are fast-growing, and a zoning regime that’s historically been friendlier to developers than to local NIMBYs has encouraged high-rise growth. Moreover, the high-rises are built in the modern boxy style (earning the ire of people who hate modern architecture) and tend to target middle-class and high-skill immigrant buyers (earning the ire of people who blame high housing costs on new construction). In contrast, vast swaths of Toronto and Vancouver are zoned for single-family housing.

And yet, Vancouver has considerable missing middle housing, too. The population density in Mount Pleasant, Fairview, Kitsilano, and West Point Grey is similar to that of Somerville and Eastern Queens. Buildings there are in modern style, but the housing typologies are not modernist towers in a park, but rather mostly buildings with 2-4 floors with the medium lot coverage typical of missing middle. I lived in an eight-unit, three-story building. Across from me there was a high-rise, but it was atypical; for the most part, that part of Vancouver is low-rise.

Shaughnessy offends people in its extravagance and wealth. In one Twitter conversation, an interlocutor who blamed absent landlords and foreigners (read: Chinese people) for Vancouver’s high housing costs still agreed with me that Shaughnessy, a white Canadian-born single-family area, shares the blame with its low-density zoning and very high residential space per person. Legalizing accessory dwelling units (“granny flats”) and townhouses in such a neighborhood faces local political headwind from the neighbors (who are still nowhere near as empowered to block rezoning as they would south of the border), but not from citywide social movements.

And yet, the density in the inner Westside neighborhoods near Broadway and Fourth Avenue is insufficient, too. It’s of course much higher than in Shaughnessy – I never really missed not owning a car living in Kitsilano – but the price signal screams “build more housing in Kits and Point Grey.”

Is missing middle transit-oriented?

Not really. In Providence the answer is absolutely not: car ownership is expected of every person who can afford it. The nearby supermarket, East Side Market, has an enormous parking lot; I’d walk, but it was obvious to me that my mode choice was not the intended use case. Even some Brown grad students owned cars (though most didn’t); at Columbia, car ownership among people below tenure-track faculty rank approaches zero. Once they own cars, people use them to take trips they wouldn’t otherwise have made, reorienting their travel patterns accordingly.

In Cambridge, car use is lower, but still substantial. The same is true of Vancouver (where outside Downtown and the West End the entire region’s density is at most missing middle, even if the typology is towers in a park and not uniformly low-rise). In Kew Gardens Hills, people seem to mostly drive as well.

This is not a universal feature of the urban middle class. In Stockholm, my postdoc advisor as far as I can tell does not own a car, and commutes to work by bike. Both there and in Basel, biking and using transit are normal and expected even among people who earn tenured academic salaries. At 7,000 people per km^2, people can forgo driving if they really want to, but most people will not do so. Only at the higher mid-rise density will they do so.

Fare Payment Without the Stasi

Last year, I saw a tip by the Metropolitan Police: if you witness any crime on a London bus and wish to report it later, you should tell the police the number on your Oyster card and then they’ll already be able to use the number to track which bus you rode and then get the names and bank accounts of all other passengers on that bus. Londoners seem to accept this surveillance as a fact of life; closed-circuit TV cameras are everywhere, even in front of the house where Orwell lived and wrote. Across the Pond, transit agencies salivate over the ability to track passenger movements through smartcards and contactless credit cards, which is framed either as the need for data or as a nebulous anti-crime measure. Fortunately, free countries have some alternative models.

In Germany, the population is more concerned about privacy. Despite being targeted by a string of communist terrorist attacks in the 1970s and 80s, it maintained an open system, without any faregates at any train station (including subways); fare enforcement in German cities relies on proof of payment with roving inspectors. Ultimately, this indicates the first step in a transit fare payment system that ensures people pay their fares without turning the payment cards into tracking devices. While Germany resists contactless payment, there are ways to achieve its positive features even with the use of more modern technology than paper tickets.

The desired features

A transit fare payment system should have all of the following features:

  1. Integration: free transfers between different transit vehicles and different modes should be built into the system, including buses, urban rail, and regional rail.
  2. Scalability: the system should scale to large metro areas with variable fares, and not just to compact cities with flat fares, which are easier to implement. It should also permit peak surcharges if the transit agency wishes to implement them.
  3. No vendor lock: switching to a different equipment manufacturer should be easy, without locking to favored contractors.
  4. Security: it should be difficult to forge a ticket.
  5. Privacy: it should not be possible to use the tickets to track passengers in most circumstances.
  6. Hospitality: visitors and occasional riders should be able to use the system with ease, with flexible options for stored value (including easy top-up options) and daily, weekly, and monthly passes, and no excessive surcharges.

Smartcard and magnetic card systems are very easy to integrate across operators; all that it takes is political will, or else there may be integrated fare media without integrated fares themselves, as in the Bay Area (Clipper can store value but there are no free transfers between agencies). Scalability is easy on the level of software; the hardest part about it is that if there are faregates then every station must have entry and exit gates, and those may be hard to retrofit. Existing smartcard technologies vary in vendor lock, but the system the US and Britain are standardizing on, contactless credit cards, is open. The real problem is in protecting privacy, which is simply not a goal in tracking-obsessed Anglo-American agencies.

The need for hospitality

Hospitality may seem like a trivial concern, but it is important in places with many visitors, which large transit cities are. Moreover, universal design for hospitality, such as easily recognizable locations for topping up stored value, is also of use to regular riders who run out of money and need to top up. Making it easy to buy tickets without a local bank account is of use to both visitors and low-income locals without full-service bank accounts. In the US, 7% of households are unbanked and another 20% are underbanked; I have no statistics for other countries, but in Sweden banks will not even give debit cards to people with outstanding debts, which suggests to me that some low-income Swedes may not have active banking cards.

New York’s MetroCard has many faults, but it succeeds on hospitality better than any other farecard system I know of: it is easy to get the cards from machines, there is only a $1 surcharge per card, and season tickets are for 7 or 30 days from activation rather than a calendar week or month. At the other end of the hospitality scale, Navigo requires users to bring a passport photo and can only load weekly and monthly passes (both on the calendar); flexible 5-day passes cost more than a calendar weekly pass.

In fact, the main reason not to use paper tickets is that hospitality is difficult with monthly passes printed on paper. Before the Compass Card debacle, Vancouver had paper tickets with calendar monthly passes, each in a different color to make it easy for the driver to see if a passenger was flashing a current or expired pass. The tickets could be purchased at pharmacies and convenience stores but not at SkyTrain stations, which only sold single-ride tickets.

ID cards and privacy

The Anglosphere resists ID cards. The Blair cabinet’s attempt to introduce national ID cards was a flop, and the Britons I was reading at the time (such as the Yorkshire Ranter) were livid. And yet, ID cards provide security and privacy. Passports are extremely difficult to forge. Israel’s internal ID cards are quite difficult to forge as well; there are occasional concerns about voter fraud, but nothing like the routine use of fake drivers’ licenses to buy drinks so common in American college culture.

At the same time, in countries that are not ruled by people who think 1984 was an uplifting look at the future, ID cards protect privacy. The Yorkshire Ranter is talking about the evils of biometric databases, and Israeli civil liberties advocates have mounted the same attack against the government’s attempt at a database. But German passports, while biometric, store data exclusively on the passport, not in any centralized database. ID cards designed around proving that you paid your fare don’t even have to use biometrics; the security level is lower than with biometrics, but the failure mode is that the occasional forger can ride without paying $100 a month (which is much less than the cost of the forgery), not that a ring of terrorists can enter the country.

Navigo’s ID cards are not hospitable, but allowing passengers to ride with any valid state-issued ID would be. Visitors either came in from another country and therefore have passports, drove in and therefore have drivers’ licenses, or flew in domestically and therefore still have ID cards. Traveling between cities without ID is still possible here and in other free European countries, but everyone has national ID cards anyway; the ID problem is mainly in the US with its low passport penetration (and secondarily Canada and Australia), and the US has no intercity public transit network to speak of outside the Northeast Corridor.

What this means is that the best way to prevent duplication of transit passes is to require ID cards. Any ID card must be acceptable, including a passport (best option), a national ID card (second best), or an American driver’s license (worst).

Getting rid of the faregates

There are approximately three first-world Western cities that have any business having faregates on their urban rail networks: London, Paris, New York. Even there, I am skeptical that the faregates are truly necessary. The Metro’s crowd control during the World Cup victory celebration was not great. New York’s faregates sometimes cause backups to the point that passengers just push the emergency doors open to exit, and then rely on an informal honor system so that passengers don’t use the open emergency doors to sneak in without payment.

Evidently, the Munich S-Bahn funnels all traffic through a single two-track city center tunnel and has 840,000 weekday users, without faregates. Only one or two trunk lines are busier in Paris, the RER A with about a million, and possibly the RER B and D if one considers them part of the same trunk (they share a tunnel but no platforms); in London, only the Central, Victoria, and Jubilee lines are busier, none by very much; in New York, none of the two-track trunks is as busy. Only the overcrowded lines in Tokyo (and a handful in Osaka, Beijing, and Shanghai) are clearly so busy that barrier-free proof-of-payment fare enforcement is infeasible.

The main reason not to use faregates is that they are maintenance-intensive and interfere with free passenger flow. But they also require passengers to insert fare media, such as a paper ticket or a contactless card, at every station. With contactless cards the system goes well beyond exact numbers of users by station, which can be obtained with good accuracy even on barrier-free systems like Transilien using occasional counts, and can track individual users’ movements. This is especially bad on systems that do not have flat fares (because then passengers tag on and off) and on systems that involve transferring with buses or regional trains and not just the subway (because then passengers have to tag on and off at the transfer points too).

Best industry practice here is then barrier-free systems. To discourage fare evasion, the agency should set up regular inspections (on moving vehicles, with unarmed civilian inspectors), but at the same time incentivize season passes. Season passes are also good for individual privacy, since all the system registers is that the passenger loaded up a monthly pass at a certain point, but beyond that can’t track where the passenger goes. All cities that have faregates except for the largest few should get rid of them and institute POP, no matter the politics.

Tickets and ID cards

In theory, the ID card can literally be the ticket. The system can store in a central database that Alon Levy, passport number [redacted], loaded a monthly pass valid for all of Ile-de-France on 2018-08-16, and the inspector can verify it by swiping my machine-readable passport. But in practice, this requires making sure the ticket machine or validator can instantly communicate this to all roving fare inspectors.

An alternative approach is to combine paper tickets with ID cards. The paper ticket would just say “I am Alon Levy, passport number [redacted], and I have a pass valid for all of Ile-de-France until 2018-09-14,” digitally signed with the code of the machine where I validated the ticket. This machine could even be a home printer, via online purchase, or a QR code displayed on a phone. Designing such a system to be cryptographically secure is easy; the real problem is preventing duplication, which is where the ID card comes into play. Without an ID card, it’s still possible to prevent duplication, but only via a cumbersome system requiring the passenger to validate the ticket again on every vehicle (perhaps even every rail car) when getting on or off.

The same system could handle stored value. However, without printing a new ticket every time a passenger validates, which would be cumbersome, it would have to fall back on communication between the validator and the handheld readers used by the inspectors. But fortunately, such communication need not be instant. Since passengers prepay with stored value, the ticket itself, saying “I am Alon Levy, passport number [redacted], and I loaded 10 trips,” is already valid, and the only communication required is when passengers run out of money; moreover, single-use tickets have a validity period of 1-2 hours, so any validator-to-inspector communication lag time of less than the validity period will be enough to ensure not to validate expired tickets. The same system can also be used to have a daily cap as in Oyster, peak surcharges, and even generally-undesirable station-to-station rather than zonal fares.

It’s even possible to design a system without single-use tickets at all. Zurich comes close, in that a 24-hour pass costs twice as much as a single-use ticket (valid for just an hour), so passengers never have any reason to get a single-use ticket. In this system there would not be any stored value, just passes for a day or more, valid in prescribed zones, with printable tickets if regular riders in one zone occasionally travel elsewhere.

The upshot here is that advanced technology is only required for printing and reading QR codes. The machines do not need to be any more complicated than ATMs or Bitcoin ATMs (insert money, receive a Bitcoin slip of paper); I don’t know how much Bitcoin ATMs cost, but regular ATMs are typically $2,000-3,000, and the most expensive are $8,000, unlike the $75,000 ticket machines used at New York SBS stations. The moving parts are software and not hardware, and can use multi-vendor cryptographic protocols. In effect, the difficult part of verifying that there is no duplication or forgery is offloaded to the state ID system.

Bus Stop Spacing and Network Legibility

I had an interesting interview of the annoying kind, that is, one where my source says something that ends up challenging me to the point of requiring me to rethink how I conceive of transportation networks. On the surface, the interview reaffirmed my priors: my source, a mobility-limited New Yorker, prefers public transit to cars and is fine with walking 500 meters to a bus stop. But one thing my source said made me have to think a lot more carefully about transit network legibility. At hand was the question of where buses should stop. Ages ago, Jarrett suggested that all other things equal (which they never are), the best stop spacing pattern is as follows:

The bus stops on the north-side arterials are offset in order to slightly improve coverage. The reason Jarrett cites this doesn’t occur much in practice is that there would also be east-west arterials. But maybe there aren’t a lot of east-west arterials, or maybe the route spacing is such that there are big gaps between major intersections in which there’s choice about which streets to serve. What to do then? My source complained specifically about unintuitive decisions about which streets get a bus stop, forcing longer walks.

In the case of the most important streets, it’s easy enough to declare that they should get stops. In Brooklyn, this means subway stations (whenever possible), intersecting bus routes, and important throughfares like Eastern Parkway or Flatbush. Right now the B44 Select Bus Service on Nostrand misses Eastern Parkway (and thus the connection to the 3 train) and the M15 SBS on First and Second Avenues misses 72nd Street (and thus the southernmost connection to Second Avenue Subway). However, there is a bigger question at hand, regarding network legibility.

Bus networks are large. Brooklyn’s current bus network is 550 km, and even my and Eric Goldwyn’s plan only shrinks it to about 340, still hefty enough that nobody can be expected to memorize it. Passengers will need to know where they can get on a stop. For the sake of network legibility, it’s useful to serve consistent locations whenever possible.

This is equally true of sufficiently large subway networks. Manhattan subway riders know that the north-south subway lines all have stops in the vicinity of 50th Street, even though the street itself isn’t especially important, unlike 42nd or 34th. In retrospect, it would have been better to have every line actually stop at 50th, and not at 49th or 51st, but the similarity is still better than if some line (say) stopped at 47th and 54th on its way between 42nd and 59th. A bad Manhattan example would be the stop spacing on the 6 on the Upper East Side, serving 68th and 77th Streets but not the better-known (and more important) 72nd and 79th.

There are similar examples of parallel subway lines, some stopping on consistent streets, and some not. There are some smaller North American examples, i.e. Toronto and Chicago, but by far the largest subway network in the world in a gridded city is that of Beijing. There, subway stops near city center are forced by transfer locations (Beijing currently has only one missed connection, though several more are planned), but in between transfers, they tend to stop on consistent streets when those streets are continuous on the grid.

But outside huge cities (or cities with especially strong grids like Chicago, Philadelphia, and Toronto), consistent streets are mostly a desirable feature for buses, not subways. Bus networks are larger and less radial, so legibility is more important there than on subways. Buses also have shorter stop spacing than subways, so people can’t just memorize the locations of some neighborhood centers with subway stops (“Nation,” “Porte de Vincennes,” etc.).

In the other direction, in cities without strong grids, streets are usually not very long, and the few streets that are long (e.g. Massachusetts Avenue in Boston) tend to be so important that every transit route intersecting them should have a stop. However, streets that are of moderate length, enough to intersect several bus lines, are common even in interrupted grids like Brooklyn’s or ungridded cities like Paris (but in London they’re rarer). Here is the Paris bus map: look at the one-way pair in the center on Rue Reaumur and Boulevard Saint-Denis (and look at how the northbound bus on Boulevard de Strasbourg doesn’t stop at Saint-Denis, missing a Metro transfer). There are a number of streets that could form consistent stops, helping make the Parisian bus network more legible than it currently is.

As with all other aspects of legibility, the main benefits accrue to occasional users and to regular riders who unfamiliar with one particular line or region. For these riders, knowing how to look for a bus stop (or subway station, in a handful of large cities) is paramount; it enables more spontaneous trips, without requiring constantly consulting maps. These occasional spontaneous trips, in turn, are likelier to happen outside the usual hours, making them especially profitable for the transit agency, since they reduce rather than raise the peak-to-base ratio. (Bus operating costs mostly scale with service-hours, but very peaky buses tend to require a lot of deadheading because they almost never begin or end their trip at a bus depot.)

The main takeaway from this is that bus network redesigns should aim to stop buses on parallel routes at consistent streets whenever possible, subject to other constraints including regular stop spacing, serving commercial nodes, and providing connections to the rail network. To the extent cities build multiple parallel subway lines, it’s useful to ensure they serve stations on consistent streets as well when there’s a coherent grid; this may prove useful if New York ever builds a subway under Utica and extends the Nostrand Avenue Line, both of which extensions were on the drawing board as recently as the 1970s.

Radial Metro Networks for Portions of Cities

I’ve harped about the necessity of radial metro networks, looking much like the following schematic:

However, in practice such pure radial networks are rare. Some networks have parallel lines (such as Paris and Beijing), nearly all have lines intersecting without a transfer at least once (the largest that doesn’t is Mexico City), some have chordal lines and not just radial or circular lines, and nearly all have lines that meet twice. Often these variations from pure radii are the result of poor planning or a street network that makes a pure radial system infeasible, but there are specific situations in which it’s reasonable for lines to meet multiple times (or sometimes even be parallel). These come from the need to built an optimal network not just for the whole city but also notable portions of it.

The unsegmented city

The diagram depicted above is a city with a single center and no obvious sub-areas with large internal travel demand. If the city is on a river, it’s not obvious from the subway map where the river passes, and it’s unlikely its non-CBD bank has a strong identity like that of the Left Bank of Paris, South London, or Brooklyn and Queens.

Among the largest metro networks in the world, the one most akin to the diagram above is Moscow. It has seven radial lines through city center (numbered 1-10, omitting the one-sided 4, the circular 5, and the yet-incomplete 8). They have some missed connections between them (3/6, 3/7, 6/9), and one pair of near-parallel lines (2/10, meeting only at Line 10’s southern terminus), but no parallel lines, and no case in which two lines cross twice. And Moscow’s development is indeed oriented toward connecting outlying areas with city center. Connections between areas outside the center are supposed to use the circular lines (5 and 14, with 11 under construction).

In a relatively monocentric city, this is fine. Even if this city is on the river, which Moscow is, it doesn’t matter too much if two neighborhoods are on the same side of the river when planning the network. Even in polycentric cities, this is fine if the sub-centers get connections via circular lines or the odd chordal line (as will eventually happen when Los Angeles builds a real subway network with such chords as Vermont and Sepulveda).

The segmented city

London and Paris are both segmented by their rivers, and their wrong sides (South London, Left Bank) both have strong regional identities, as does to some extent East London. New York, partitioned into boroughs by much wider waterways than the Thames and Seine, has even stronger sub-identities, especially in Brooklyn. I do not know of a single New Yorker whose commute to work or school involves crossing a bridge over a river on foot, nor of any case of anyone crossing a bridge in New York on foot (or bike) except for recreational purposes; in Paris I do so habitually when visiting the Latin Quarter, and at a conference in 2010 another attendee biked from Porte de Vincennes to Jussieu every day.

With a difficult water boundary, the wrong-side part of the city became a center in its own right. Downtown Brooklyn and the Latin Quarter should both be viewed as sub-centers that failed to become CBDs. The Latin Quarter, the oldest part of Paris outside the Ile de la Cite, declined in favor of the more commercial Right Bank as the city grew in the High and Late Middle Ages; Downtown Brooklyn declined in favor of more concentration in Manhattan and more dispersion to other centers (often in Queens) over the course of the 20th century.

Early 20th century New York and Paris were not polycentric cities. There was no everywhere-to-everywhere demand. There was demand specifically for travel within Brooklyn and within the Left Bank. To this day, the connections to the Latin Quarter from Right Bank neighborhoods not on Line 4 are not great, and from Nation specifically the alternatives are a three-seat ride and a long interchange at Chatelet. Ultimately, this situation occurs when you have a region with a strong identity and strong demand for internal travel larger than a neighborhood (which can be served by a few subway stops on a single line) but smaller than an entire city.

In this case, a radial subway network (which neither the New York City Subway nor the Paris Metro is) could justifiably have multiple crossings between two lines, ensuring that lines provide a coherent network for internal travel. South London is a partial example of this principle: not counting the Wimbledon branch of the District line, the South London Underground network is internally connected, and the best route between any two South London stations stays within South London. In particular, the Victoria and Northern lines cross twice, once at Stockwell and once at Euston, in a city that has a generally radial metro system.

Don’t go overboard

The need to serve internal travel within portions of a city is real, and it’s worthwhile to plan metro networks accordingly. But at the same time, it’s easy to go overboard and plan lines that serve only travel within such portions. Most of the examples I give of weak chordal lines – the G train in New York, Line 10 and the RER C in Paris, Line 6 in Shanghai – serve internal demand to the wrong side of a city divided by a river; only Shanghai’s Line 3 is an exception to this pattern, as a weak chordal line that doesn’t come from city segmentation.

In the cases of the G and M10, the problem is partly that the lines have compromises weakening them as radials. The G has too many missed connections to radial lines, including the J/Z and the entire Atlantic-Pacific complex; M10 terminates at Austerlitz instead of extending east to the library, which is the second busiest Left Bank Metro stop (after Montparnasse) and which has a particularly strong connection to the universities in the Latin Quarter.

But Line 6 is constrained because it doesn’t serve Lujiazui, just Century Avenue, and the RER C does serve the library but has exceptionally poor connections to the CBD and other Right Bank destinations. It’s important to ensure the network is coherent enough to serve internal demand to a large segment of the city but also to serve travel demand to the rest of the city well.

Good transfers

Serving the entire city hinges on good transfers. The most important destination remains city center, so lines that aren’t circumferential should still aim to serve the center in nearly all cases. Internal demand should be served with strategic transfers, which may involve two lines crossing multiple times, once in or near city center and once on the wrong side of the river.

The main drawback of multiple crossings is that they are less efficient than a pure radial network with a single city center crossing between each pair of lines, provided the only distinguished part of the city is the center. Once internal travel to a geographic or demographic segment is taken into account, there are good reasons to slightly reduce the efficiency of the CBD-bound network if it drastically raises the efficiency of the secondary center-bound network. While demographic trends may come and go (will Flushing still be an unassimilated Chinese neighborhood in 50 years?), geographic constraints do not, and place identities like “Left Bank” and “Brooklyn” remain stable.

Note the qualifiers: since the CBD remains more important than any secondary center, it’s only acceptable to reduce CBD-bound efficiency if the gain in secondary center-bound efficiency is disproportionate. This is why I propose making sure there are good transfers within the particular portion of the city, even at the cost of making the radial network less perfect: this would still avoid missed connections, a far worse problem than having too many transfer points.

So what?

In New York, London, and Paris, the best that can be done is small tweaks. However, there exist smaller or less developed cities that can reshape their transit networks, and since cities tend to form on rivers and bays, segmentation is common. Boston has at least two distinguished wrong-side segments: East Boston (including Chelsea and Revere) and Greater Cambridge. East Boston can naturally funnel transit through Maverick, but in Greater Cambridge there will soon be two separate subway spines, the Red and Green Lines, and it would be worthwhile to drag a rail connection between them. This is why I support investing in rail on the Grand Junction, turning it into a low-radius circular regional rail line together with the North-South Rail Link: it would efficiently connect the Green Line Extension with Kendall.

More examples of segmented cities include the Bay Area (where the wrong-side segment is the East Bay), Istanbul (where Europe and Asia have separate metro networks, connected only by Marmaray), Stockholm (where Södermalm and Söderort are separated by a wide channel from the rest of the city, and Kungsholmen is also somewhat distinguished), and Washington (where the wrong side is Virginia). In all of these there are various compromises on metro network planning coming from the city segmentation. Stockholm’s solution – making both the Red and Green Lines serve Slussen – is by far the best, and the Bay Area could almost do the same if BART were connected slightly differently around Downtown Oakland. But in all cases, there are compromises.